bcma: fix building without OF_IRQ

The bcma driver core can be built with or without DT support, but
it fails to build when CONFIG_OF=y and CONFIG_OF_IRQ=n, which
can happen on platforms that do not support IRQ domains.

ERROR: "irq_create_of_mapping" [drivers/bcma/bcma.ko] undefined!
ERROR: "of_irq_parse_raw" [drivers/bcma/bcma.ko] undefined!
ERROR: "of_irq_parse_one" [drivers/bcma/bcma.ko] undefined!

This adds another compile-time check for OF_IRQ, but also
gets rid of now unneeded #ifdef checks: Using the simpler
IS_ENABLED() check for OF_IRQ also covers the case of not
having CONFIG_OF enabled. The check for CONFIG_OF_ADDRESS
was added to allow building on architectures without
OF_ADDRESS, but that has been addressed already in
b1d06b60

 ("of: Provide static inline function for
of_translate_address if needed").

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>